U.S. Department of Justice Office of Justice Programs Bureau of Justice Statistics ------------------------------------------------------- This file is text only without graphics and many of the tables. A Zip archive of the tables in this report in spreadsheet format (.csv) and the full report including tables and graphics in .pdf format are available on BJS website at: http://www.bjs.gov/index.cfm?ty=pbdetail&iid=4884 This report is one in a series. More recent editions may be available. To view a list of all in the series go to http://bjs.gov/index.cfm?ty=pbse&sid=62 ------------------------------------------------------- ******************* Statistical Tables ******************* Crime Against Persons with Disabilities, 2009–2012 - Statistical Tables Erika Harrell, Ph.D., BJS Statistician Persons age 12 or older who had disabilities experienced 1.3 million nonfatal violent crimes in 2012 (table 1). Nonfatal violent crimes include rape, sexual assault, robbery, aggravated assault, and simple assault. The annual number of nonfatal violent victimizations against persons with disabilities increased from 2008 to 2012. However, no statistically significant change was found in the number of violent victimizations from 2011 to 2012. The findings in this report are based on the Bureau of Justice Statistics’ (BJS) National Crime Victimization Survey (NCVS), a household survey that collects data on U.S. residents age 12 or older (excluding those living in institutions). The NCVS adopted survey questions from the U.S. Census Bureau’s American Community Survey (ACS) to identify respondents with disabilities. The NCVS defines disability as the product of interactions among individuals’ bodies; their physical, emotional, and mental health; and the physical and social environment in which they live, work, or play. Disability exists where this interaction results in limitations of activities and restrictions to full participation at school, at work, at home, or in the community. Disabilities are classified according to six limitations: hearing, vision, cognitive, ambulatory, self- care, and independent living. Data from the ACS and the 2000 U.S. Standard Population from the Decennial Census were used to estimate age-adjusted victimization rates for persons with and without disabilities. For this report, victimization rates were generated by using the ACS population estimates for persons with disabilities. The Methodology further details data sources, computation procedures, and data limitations. Statistical tables in this report detail the level and rates of nonfatal violent victimization against persons with and without disabilities, describe the types of disabilities, and compare victim characteristics. With the exception of table 1, all estimates are based on 2-year rolling averages centered on the most recent year. For example, estimates reported for 2012 represent the average estimates for 2011 and 2012. This method improves the reliability and stability of estimate comparisons over time. ***************** List of tables ***************** Table 1. Annual number of violent crimes, by type of crime and victim’s disability status, 2008–2012 Table 2. Unadjusted violent victimization rates, by victim’s disability status and age, 2009–2012 Table 3. Age-adjusted and unadjusted rates of violent victimization for persons with disabilities, by type of crime, 2009–2012 Table 4. Age-adjusted and unadjusted rates of violent victimization for persons without disabilities, by type of crime, 2009–2012 Table 5. Age-adjusted rates of violent victimization, by victim’s disability status, sex, race, and Hispanic origin, 2009–2012 Table 6. Percent of violence against persons with disabilities that involved victims with multiple disability types, by type of crime, 2009–2012 Table 7. Age-adjusted rates of violent victimization, by type of crime and number of disability types, 2009–2012 Table 8. Unadjusted rate of violent victimization against persons with disabilities, by disability type, 2009–2012 Table 9. Unadjusted rate of serious violent victimization against persons with disabilities, by disability type, 2009– 2012 Table 10. Unadjusted rate of simple assault against persons with disabilities, by disability type, 2009–2012 Table 11. Unadjusted violent victimization rate, by victim’s sex and disability type, 2009–2012 ************************* List of appendix tables ************************* Appendix Table 1. Standard errors for table 1: Annual number of violent crimes, by type of crime and victim’s disability status, 2008–2012 Appendix Table 2. Standard errors for table 2: Unadjusted violent victimization rates, by victim’s disability status and age, 2009–2012 Appendix Table 3. Standard errors for table 3: Age-adjusted and unadjusted rates of violent victimization for persons with disabilities, by type of crime, 2009–2012 Appendix Table 4. Standard errors for table 4: Age-adjusted and unadjusted rates of violent victimization for persons without disabilities, by type of crime, 2009–2012 Appendix Table 5. Standard errors for table 5: Age-adjusted rates of violent victimization, by victim’s disability status, sex, race, and Hispanic origin, 2009–2012 Appendix Table 6. Standard errors for table 6: Percent of violence against persons with disabilities that involved victims with multiple disability types, by type of crime, 2009–2012 Appendix Table 7. Standard errors for table 7: Age-adjusted rates of violent victimization, by type of crime and number of disability types, 2009–2012 Appendix Table 8. Standard errors for table 8: Unadjusted rate of violent victimization against persons with disabilities, by disability type, 2009–2012 Appendix Table 9. Standard errors for table 9: Unadjusted rate of serious violent victimization against persons with disabilities, by disability type, 2009–2012 Appendix Table 10. Standard errors for table 10: Unadjusted rate of simple assault against persons with disabilities, by disability type, 2009–2012 Appendix Table 11. Standard errors for table 11: Unadjusted violent victimization rate, by victim’s sex and disability type, 2009–2012 Appendix Table 12. Annual number and percent of U.S. population with disabilities, by demographic characteristics, 2008–2012 Appendix Table 13. Annual number and percent of U.S. population without disabilities, by demographic characteristics, 2008–2012 Appendix Table 14. U.S. population according to the Census Bureau’s ACS and PUMS data, by victim’s disability status and demographic characteristics, 2010 Appendix Table 15. U.S. population calculated and according to the Census Bureau’s PUMS data, by victim’s disability status and demographic characteristics, 2011 Appendix Table 16. Unadjusted rate of violent victimization, by victim’s disability status, sex, race, and Hispanic origin, 2009–2012 Appendix Table 17. Standard errors for appendix table 16: Unadjusted rate of violent victimization, by victim’s disability status, sex, race, and Hispanic origin, 2009–2012 Appendix Table 18. Unadjusted rate of violent victimization against persons with disabilities, by type of crime and number of disability types, 2009–2012 Appendix Table 19. Standard errors for appendix table 18: Unadjusted rate of violent victimization against persons with disabilities, by type of crime and number of disability types, 2009–2012 ******************************* Violent crime by victim’s age and disability status ******************************* * Among persons ages 12 to 15, the unadjusted rate of violent victimization was nearly three times higher for persons with disabilities (123 per 1,000) than for persons without disabilities (43 per 1,000) in 2012 (table 2). * In 2012, among persons ages 16 to 19, persons with disabilities had an unadjusted rate of violent victimization (102 per 1,000) that was about 2.5 times higher than that of persons without disabilities (41 per 1,000). * The rate of violent victimization among persons with disabilities ages 12 to 15 increased from 77 per 1,000 in 2011 to 123 per 1,000 in 2012. * No statistically significant difference was found in the unadjusted rate of violent victimization among persons with disabilities ages 16 to 19 from 2011 (123 per 1,000) to 2012 (102 per 1,000). * The unadjusted rate of violent victimization among persons with disabilities ages 25 to 34 increased from 54 per 1,000 in 2011 to 83 per 1,000 in 2012. * The unadjusted rate of violent victimization against persons with disabilities age 50 to 64 slightly increased from 2011 (20 per 1,000) to 2012 (28 per 1,000).***Footnote 1Differences described as slight or slightly passed a test at the 0.10 level of statistical significance (90% confidence level). Caution is required when comparing estimates not explicitly discussed in this report. ****************************************************** ******************************** The use of age-adjusted rates ******************************** Direct comparisons of the violent victimization rate between persons with and without disabilities without taking into account the differences in age distributions between the two populations can be misleading. The age distribution of persons with disabilities differs considerably from that of persons without disabilities, and violent crime victimization rates vary significantly with age. To compare rates of violent victimization by disability status, an age adjustment method was used to handle the differences in age istributions of persons with disabilities and without disabilities. According to the ACS, persons with disabilities are generally older than persons without disabilities. For example, about 42% of persons with disabilities were age 65 or older in 2012, compared to 12% of persons without disabilities. The age adjustment standardizes the rate of violence for persons with and without disabilities to show what the rates would be if they had the same age distribution as the 2000 U.S. Standard Population as calculated by the U.S. Census Bureau. ****************************************************** ******************************** Violent crime by type of crime ******************************** * In 2012, the age-adjusted rate of violent victimization for persons with disabilities (60 per 1,000 persons with disabilities) was nearly three times the rate among persons without disabilities (22 per 1,000 persons without disabilities) (table 3 and table 4). * In 2012, the age-adjusted rate of serious violent victimization for persons with disabilities (22 per 1,000) was more than three times higher than that for persons without disabilities (6 per 1,000). * During 2012, serious violence (rape or sexual assault, robbery, and aggravated assault) accounted for about 38% of nonfatal violent crime against persons with disabilities, which was higher than the percentage found for persons without disabilities (29%) (not shown). * In 2012, the age-adjusted rate of simple assault against persons with disabilities (38 per 1,000) was more than twice that for persons without disabilities (16 per 1,000). * No statistically significant difference was found in the rate of violent victimization against persons with disabilities from 2009 to 2012. Similarly, the rate of violent victimization remained stable against persons without disabilities from 2009 (22 per 1,000) to 2012 (22 per 1,000). * From 2011 to 2012, the age-adjusted rates of simple assault against persons with and without disabilities increased. * Among persons with and without disabilities, no statistically significant differences were detected in robbery from 2009 to 2012. * Among persons with disabilities, the rate of rape and aggravated assault increased from 2009 to 2012. * Violent crime rates by sex, race, and Hispanic origin ******** Sex ******** * In 2012, the age-adjusted rate of violent victimization was higher for persons with disabilities than for those without disabilities for both males and females (table 5). * The rate of violence against males with disabilities was 59 per 1,000 in 2012, compared to 25 per 1,000 for males without disabilities. * For females with disabilities, the rate of violence was 62 per 1,000 in 2012, compared to 20 per 1,000 females without disabilities. * In 2012, no statistically significant difference was found in the rate of violent victimization against males with disabilities (59 per 1,000) and females with disabilities (62 per 1,000). * The age-adjusted rate of violence against males with disabilities increased from 39 to 59 per 1,000 from 2009 to 2012. However, no statistically significant difference was found for females over the same period. *************************** Race and Hispanic origin *************************** * For each racial group measured, persons with disabilities had higher age-adjusted violent victimization rates than persons without disabilities in 2012. * For each of the racial groups examined, no statistically significant difference was found among persons with disabilities in the age-adjusted rate of violent victimization for 2009 and 2012. * In 2012, whites with disabilities (67 per 1,000) had a higher age-adjusted rate of violent victimization than blacks with disabilities (46 per 1,000). * Among persons with disabilities, other races (American Indian or Alaska Native; and Asian, Native Hawaiian, or other Pacific Islander) had a lower rate of violence (33 per 1,000) than whites (67 per 1,000) and persons of two or more races (76 per 1,000) in 2012. * Among persons with and without disabilities, Hispanics had a lower rate of violent victimization than non-Hispanics in 2012. * Among both Hispanics and non-Hispanics, persons with disabilities had a higher rate of violent victimization than persons without disabilities in 2012. ******************************************** Violent crime by number of disability types ******************************************** * In 2012, 52% of nonfatal violent crime against persons with disabilities involved victims who had multiple disability types. While this was not statistically different from the percentage found in 2011 (57%), it was an increase from 2009 (41%) (table 6). * From 2009 to 2012, the percentage of violent victimization against persons with disabilities in which the victim had multiple disability types increased for rape or sexual assault and robbery. * In 2012, persons with one disability type (53 per 1,000) were less likely than persons with multiple disability types to be violently victimized (table 7). * In 2012, no statistically significant difference was found between the age-adjusted rate of serious violent victimization against persons with one disability type (19 per 1,000) and persons with multiple disability types (25 per 1,000). * The age-adjusted rate of violent crime against persons with one disability type increased from 37 per 1,000 in 2011 to 53 per 1,000 in 2012. Among persons with multiple disability types, no statistically significant difference was found in the 2011 and 2012 age-adjusted rate of violent victimization. ******************** Types of disability ********************* * Persons with cognitive disabilities had the highest unadjusted rate of violent victimization from 2009 to 2012 (table 8). * No statistically significant difference was found in the 2009 and 2012 rates of violent victimization against persons with hearing or vision disabilities. * In 2012, persons with ambulatory disabilities (30 per 1,000) had a higher rate of violent victimization than persons with hearing disabilities (20 per 1,000). * No statistically significant difference was found in the 2012 rates of violent victimization against persons with hearing (20 per 1,000) and vision (25 per 1,000) disabilities. * Among persons with cognitive disabilities, the rate of serious violent crime doubled across the study period from 12 per 1,000 in 2009 to 24 per 1,000 in 2012 (table 9). * The rate of serious violent victimization against persons with self-care disabilities nearly tripled from 2009 (4 per 1,000) to 2012 (11 per 1,000). * The unadjusted rate of simple assault against persons with cognitive disabilities increased from 27 per 1,000 in 2011 to 40 per 1,000 in 2012 (table 10). * In 2012, among persons with hearing, vision, cognitive, or independent living disabilities, no differences were detected in the unadjusted rates of violent victimization by victim’s sex (table 11). * Males with ambulatory or self-care disabilities had higher rates of violent victimization than females with the same disability types in 2012. ******************************* Among males with disabilities— ******************************* * With the exception of those with ambulatory or cognitive disabilities, no changes were detected in the unadjusted rate of violent victimization with any disability type from 2011 to 2012. * From 2011 to 2012, the unadjusted rate of violent victimization against males with ambulatory disabilities increased from 25 per 1,000 to 39 per 1000. * The unadjusted rate of violent victimization against males with cognitive disabilities increased from 49 per 1,000 in 2011 to 66 per 1,000 in 2012. ********************************* Among females with disabilities— ********************************* * For each disability type measured, no statistically significant difference was found between the 2011 and 2012 rates of violent victimization against females. ************** Methodology ************** Survey coverage ************** The National Crime Victimization Survey (NCVS) is an ongoing data collection conducted by the U.S. Census Bureau for the Bureau of Justice Statistics (BJS). The NCVS is a self-report survey in which interviewed persons are asked about the number and characteristics of victimizations experienced during the prior 6 months. The NCVS collects information on nonfatal personal crimes (rape or sexual assault, robbery, aggravated and simple assault, and personal larceny) and household property crimes (burglary, motor vehicle theft, and other theft) both reported and not reported to police. In addition to providing annual level and change estimates on criminal victimization, the NCVS is the primary source of information on the nature of criminal victimization incidents. Survey respondents provide information about themselves (e.g., age, sex, race and Hispanic origin, marital status, education level, and income) and whether they experienced a victimization. Information is collected for each victimization incident about the offender (e.g., age, race and Hispanic origin, sex, and victim-offender relationship), characteristics of the crime (including time and place of occurrence, use of weapons, nature of injury, and economic consequences), whether the crime was reported to police, reasons the crime was or was not reported, and experiences with the criminal justice system. The NCVS is administered to persons age 12 or older from a nationally representative sample of households in the United States. The NCVS defines a household as a group of members who all reside at a sampled address. Persons are considered household members when the sampled address is their usual place of residence at the time of the interview and when they have no usual place of residence elsewhere. Once selected, households remain in the sample for 3 years, and eligible persons in these households are interviewed every 6 months either in-person or over the phone, for a total of seven interviews. Generally, all first interviews are conducted in-person. New households rotate into the sample on an ongoing basis to replace outgoing households that have been in the sample for the 3-year period. The sample includes persons living in group quarters, such as dormitories, rooming houses, and religious group dwellings, and excludes persons living in military barracks and institutional settings, such as correctional or hospital facilities, and the homeless. (For more information, see the Survey Methodology for Criminal Victimization in the United States, 2008, NCJ 231173, BJS web, May 2011.) In 2007, the NCVS adopted questions from the U.S. Census Bureau’s American Community Survey (ACS) to measure the rate of victimization against people with disabilities. The NCVS does not identify persons in the general population with disabilities. The ACS Subcommittee on Disability Questions developed the disability questions based on questions used in the 2000 Decennial Census and earlier versions of the ACS. The questions identify persons who may require assistance to maintain their independence, be at risk for discrimination, or lack opportunities available to the general population because of limitations related to a prolonged (6 months or longer) sensory, physical, mental, or emotional condition. More information about the ACS and the disability questions is available on the U.S. Census Bureau website at http://www.census.gov/acs/www/. ***************************************** Changes to the disability questions in the NCVS and ACS in 2008 ***************************************** In 2008, the U.S. Census Bureau changed some of the disability questions on the ACS. The question about sensory disability was separated into two questions about blindness and deafness, and the questions about physical disability were asked only about serious difficulty walking or climbing stairs. Also, questions on employment disability and going outside of the home were eliminated in 2008. Census Bureau analysis of 2007 and 2008 ACS disability data revealed significant conceptual and measurement differences between the 2007 and 2008 disability questions. The Census Bureau concluded that data users should not compare the 2007 estimates of the population with disabilities and those of later years. Because the 2007 and 2008 NCVS disability questions mirrored the ACS, estimates of victimization of people with disabilities from the 2007 and 2008 NCVS should not be compared. As a result, the 2007 disability data are not presented in this report. Further explanation about incomparability of the 2007 and 2008 ACS disability data is available at http://www.census.gov/acs/www/Downloads/methodology/content_t est/P4_Disability.pdf. ***************************************** Definitions of disability types ***************************************** Disabilities are classified according to six limitations: hearing, vision, cognitive, ambulatory, self-care, and independent living. * Hearing limitation entails deafness or serious difficulty hearing. * Vision limitation is blindness or serious difficulty seeing, even when wearing glasses. * Cognitive limitation includes serious difficulty in concentrating, remembering, or making decisions because of a physical, mental, or emotional condition. * Ambulatory limitation is difficulty walking or climbing stairs. * Self-care limitation is a condition that causes difficulty dressing or bathing. * Independent living limitation is a physical, mental, or emotional condition that impedes doing errands alone, such as visiting a doctor or shopping. ***************************************** Disability questions included in the NCVS from 2008 through 2012 ***************************************** Questions 169a through 173 169a. Are you deaf or do you have serious difficulty hearing? 169b. Are you blind or do you have serious difficulty seeing even when wearing glasses? 170a. Because of a physical, mental, or emotional condition, do you have serious difficulty: * concentrating, remembering, or making decisions? * walking or climbing stairs? * dressing or bathing? 170b. Because of a physical, mental, or emotional condition, do you have difficulty doing errands alone such as visiting a doctor’s office or shopping? 171. Is “Yes” marked in any of 169a–170b? (That is, has the respondent indicated that he/she has a health condition or disability?) 172. During the incident you just told me about, do you have reason to suspect you were victimized because of your health condition(s), impairment(s), or disability(ies)? 173. What health conditions, impairments, or disabilities do you believe caused you to be targeted for this incident? In the ACS, persons ages 12 to 14 are not asked about having an independent living disability and are therefore not included in the populations with independent living disabilities. Even though crime victims ages 12 to 14 receive this question in the NCVS (question 170b), victims ages 12 to 14 who respond affirmatively are excluded from rates of violent victimization against persons with an independent living disability in order to match the age limitations for having an independent living disability in the ACS (age 15 or older). In this report, rates of violence against persons with an independent living disability are per 1,000 persons age 15 or older, compared to rates per 1,000 persons ages 12 or older for other disability types. Also, violent crime victims ages 12 to 14 who report in the NCVS that they have an independent living disability and no other disability are classified as not having a disability to be compatible with age limits on disability definitions in the ACS. ******************************** Limitations of the estimates ******************************** The NCVS was designed to measure the incidence of criminal victimization against the U.S. civilian household population, excluding persons who live in institutions and the homeless. In this report, institutions refer to adult correctional facilities, juvenile facilities, nursing facilities or skilled nursing facilities, in-patient hospice facilities, residential schools for people with disabilities, and hospitals with patients who have no usual home elsewhere, as defined by the ACS. The measures of crime against persons with disabilities (as measured by the NCVS) cover only people with disabilities who are living among the general population in household settings. Subsequently, there is some coverage error in using just the noninstitutionalized population. For example, according to the ACS, about 96% of the 1.3 million persons age 65 or older living in institutions had disabilities in 2012. Because persons in these facilities would not be covered in the NCVS, estimates of violence against these persons are not counted. The lack of information from the institutions will result in an undercount of violence against persons with disabilities. Certain aspects of the NCVS design can also contribute to an underestimation of the level or type of violence against persons with disabilities. For example, the survey instruments, modes of interview, and interviewing protocols used in the NCVS may not be suited for interviewing people with difficulty communicating, especially by telephone. Some people have disabilities that limit their verbal communication and use technology to enhance their ability to communicate, but many people do not have access to such technology. Proxy interviews may also lead to an underestimate of violence against persons with disabilities. The survey requires direct interviews with eligible respondents and allows the use of proxy interviews with a caregiver or other eligible party in a limited set of circumstances. A proxy interview is allowed when a respondent is physically or mentally incapable of responding. The survey restrictions on proxy interviews were instituted because someone else may not know about the victimization experiences of the respondent, and because the person providing the information via proxy may be the perpetrator of the abuse or violence experienced by the respondent. Since proxy respondents may be more likely to omit crime incidents or may not know some details about reported crime incidents, the number or types of crimes against persons with disabilities may be underestimated. In 2012, about 2% of violent crime incidents against persons with disabilities were obtained from proxy interviews. In addition, in 2012, 86% of the violent incidents against persons with disabilities conducted by proxy interviews were for simple assault, compared to about 60% of violent incidents against persons with disabilities conducted from nonproxy interviews (not shown). ******************************************* Disability population in the United States ******************************************* According to the ACS, about 14% of the U.S. population age 12 or older living outside of institutions in 2012 had a disability. Characteristics of the population with and without disabilities are compared in appendix tables 12 and 13. In 2012, among noninstitutionalized persons with disabilities, 48% were male and 52% were female. Whites accounted for about 77% of the population with disabilities, blacks accounted for 14%, and persons of two or more races accounted for 2%. About 11% were Hispanic. About 70% of the population with disabilities was age 50 or older, compared to about 34% of the population of persons without disabilities. The sex, race, Hispanic origin, and age distributions of persons with a disability living outside of institutions did not change substantially between 2011 and 2012. The 2011 and 2012 ACS population estimates of persons by disability status were generated from Public Use Microdata Sample (PUMS) data (see below). ***************************************** Public Use Microdata Sample (PUMS) data ***************************************** To generate populations of persons by disability status for 2008 through 2010, the Census Bureau generated these estimates for the Bureau of Justice Statistics (BJS) from the full, confidential ACS dataset. Due to budgetary restrictions, PUMS data from the Census Bureau’s ACS were used to calculate populations of persons by disability status for 2011 and 2012. The ACS PUMS dataset is a sample of population and housing unit records from the American Community Survey. Usually, the PUMS files include only about two-thirds of the cases contained in the larger confidential dataset. The ACS PUMS files include the actual responses collected in ACS questionnaires, although some responses have been edited to protect confidentiality of respondents. The ACS PUMS file included sample weights for each person and housing unit, which were applied to the individual records to expand the sample to estimate totals and percentages of the full population. Estimates of the 2010 U.S. population by disability status taken from the custom tabulations from the Census Bureau were compared with the same estimates generated using PUMS data (appendix table 14). Even though the counts generated from custom tabulations from the Census Bureau differ from that generated from the PUMS data for each demographic group within both disability statuses, no systematic differences were detected. For more information on PUMS data from the Census Bureau, please see: http://www.census.gov/acs/www/data_documentation/public_use_m icrodata_sample/. ***************************************** Comparing 2011 computed populations to 2011 populations generated with PUMS data ***************************************** In the previous report, Crime Against Persons with Disabilities, 2009–2011 - Statistical Tables (NCJ 240299, BJS web, December 2012), BJS used population estimates that were computed using 2010 proportions of the population by disability status from the ACS. BJS did this because, at the time, the 2011 populations by disability status were not available from the ACS. However, the 2011 populations by disability status were available for this report via the PUMS data. BJS compared the two 2011 populations (calculated from the demographic information in the 2010 ACS and estimates from the PUMS data for the 2011 ACS) (appendix table 15). Even though the calculated counts differ from the ACS counts for each demographic group within both disability statuses, no systematic differences were detected between the calculated populations and the 2011 ACS populations generated with PUMS data. ******************************************** Direct standardization with the 2000 U.S. Standard Population *** ********************************************* Footnote 2 ?For more information on direct standardization, see Curtin, L.R. & Klein, R.J. (1995). Direct standardization (age-adjusted death rates). Healthy People 2000: Statistical Notes, 6 Revised. Available at http://www.cdc.gov/nchs/data/statnt/statnt06rv.pdf.*** The method used to generate age-adjusted rates of violent victimization presented in this report was direct standardization with the 2000 U.S. Standard Population from the Decennial Census as the standard population. Age-adjusted standardization eliminates the problem of different age distributions between and within groups. In general, persons with disabilities are an older population than persons without disabilities. Because crime rates vary by age, direct standardization produces age-adjusted rates that would occur if both populations had the same age distribution as the standard population. The 2000 U.S. Standard Population was created by the U.S. Census Bureau Population Projection Program (http://www.census.gov/population/projections/), which uses data from the Current Population Survey. To calculate age groups using the 2000 U.S. Standard Population, populations of single years of age were obtained for persons age 12 or older from the Census P25–1130 (http://www.census.gov/prod/1/pop/p25-1130.pdf) series estimates of the 2000 populations generated by the U. S. Census Bureau Population Projection Program. These single- year populations for persons age 12 or older were then summed to create the following age groups: ages 12 to 15, 16 to 19, 20 to 24, 25 to 34, 35 to 49, 50 to 64, and 65 or older. In this report, the total standard population refers to the 2000 U.S. Standard Population age 12 or older. All weights created for this report based on the 2000 U.S. Standard Population are not race- or sex-specific, so they do not adjust for differences in the racial or sex distributions between populations of persons with and without disabilities. There is little difference in the race and sex distributions between populations of persons with and without disabilities. According to the 2012 ACS, among noninstitutionalized persons with disabilities, about 48% were male and 52% were female, compared to 49% of persons without disabilities being male and 51% being female. Whites accounted for 77% of persons with disabilities and 75% of persons without disabilities. Blacks accounted for about 14% of persons with disabilities and about 12% of persons without disabilities. Persons of other racial groups accounted for about 7% of persons with disabilities and about 11% of persons without disabilities. Persons of two or more races made up the same percentage (about 2%) of the population with and without disabilities. Hispanics accounted for about 11% of persons with disabilities and about 16% of persons without disabilities in 2012. Non-Hispanics accounted for about 89% of persons with disabilities and about 84% of persons without disabilities. The violent victimization rate, age-adjusted using direct standardization with the 2000 U.S. Standard Population (Rd) is calculated as— Rd = ? (wa * ra) where Rd = age-adjusted rate of violent victimization of the population of interest calculated using direct standardization wa = weight calculated from the 2000 U.S. Standard Population for age group a ra = unadjusted rate of violent victimization for age group a. The weight (wa) for age group a is calculated as— wa = na / N where wa = weight calculated from the 2000 U.S. Standard Population for age group a na = number of persons in age group a in the 2000 U.S. Standard Population N = total number of persons in the 2000 U.S. Standard Population. This method produces rates of violent victimization as if the population of interest had the same age distribution as the 2000 U.S. Standard Population. To use this method to produce age-adjusted rates of violent victimization for persons with disabilities, ra would represent the unadjusted violent victimization rate against persons with disabilities in age group a. To calculate the violent victimization rate of persons without disabilities, ra would represent the unadjusted violent victimization rate against persons without disabilities in age group a. **************** Property crime **************** In the first two reports in this series, Crime Against People with Disabilities, 2007 (NCJ 227814, BJS web, October 2009) and Crime Against People with Disabilities, 2008 (NCJ 231328, BJS web, December 2010), property crime by disability status was included. These statistics are not included in this report due to potential underreporting of property crimes against persons with disabilities. The NCVS measure of property crime is a household-based measure. The questions NCVS uses to identify whether a person has a disability are asked only of those respondents who reported that they have been victimized. If the person who reports the property crime is a household member with a disability, then the NCVS identifies the property crime as one against a household that has a person with a disability. If a household member without a disability reports the property crime during the survey, the NCVS does not ask whether any other household member has a disability. For this reason, any estimate of property crime against people with disabilities using the NCVS may be an undercount of such crimes. As a result, information regarding property crime is not included in this report. ************************************** Nonresponse and weighting adjustments ************************************** In 2012, 92,390 households and 162,940 persons age 12 or older were interviewed for the NCVS. Each household was interviewed twice during the year. The response rate was 87% for households and 87% for eligible persons. Victimizations that occurred outside of the United States were excluded from this report. In 2012, less than 1% of the unweighted victimizations occurred outside of the United States and were excluded from the analyses. Estimates in this report use data from the 2008 to 2012 NCVS data files weighted to produce annual estimates for persons age 12 or older living in U.S. households. Because the NCVS relies on a sample rather than a census of the entire U.S. population, weights are designed to inflate sample point estimates to known population totals and to compensate for survey nonresponse and other aspects of the sample design. The NCVS data files include both household and person weights. The household weight is commonly used to calculate estimates of property crimes, such as motor vehicle theft or burglary, which are identified with the household. Person weights provide an estimate of the population represented by each person in the sample. Person weights are most frequently used to compute estimates of crime victimizations of persons in the total population. After proper adjustment, both household and person weights are also used to form the denominator in calculations of crime rates. The victimization weights used in this analysis account for the number of persons present during an incident and for repeat victims of series incidents. The weight counts series incidents as the actual number of incidents reported by the victim, up to a maximum of ten incidents. Series victimizations are victimizations that are similar in type but occur with such frequency that a victim is unable to recall each individual event or to describe each event in detail. Survey procedures allow NCVS interviewers to identify and classify these similar victimizations as series victimizations and collect detailed information on only the most recent incident in the series. In 2012, series incidents accounted for about 1% of all victimizations and 4% of all violent victimizations. The approach to weighting series incidents as the number of incidents up to a maximum of ten produces more reliable estimates of crime levels, while the cap at ten minimizes the effect of extreme outliers on the rates. Additional information on the series enumeration is detailed in the report Methods for Counting High Frequency Repeat Victimizations in the National Crime Victimization Survey, NCJ 237308, BJS web, April 2012. *********************************** Standard error computations for percentages and unadjusted rates *********************************** When national estimates are derived from a sample, as is the case with the NCVS, caution must be taken when comparing one estimate to another or when comparing estimates over time. Although one estimate may be larger than another, estimates based on a sample have some degree of sampling error. The sampling error of an estimate depends on several factors, including the amount of variation in the responses, the size of the sample, and the size of the subgroup for which the estimate is computed. When the sampling error around the estimates is taken into consideration, the estimates that appear different may not be statistically different. One measure of the sampling error associated with an estimate is the standard error. The standard error can vary from one estimate to the next. In general, for a given metric, an estimate with a smaller standard error provides a more reliable approximation of the true value than an estimate with a larger standard error. Estimates with relatively large standard errors are associated with less precision and reliability and should be interpreted with caution. In order to generate standard errors around numbers and estimates from the NCVS, the Census Bureau produces generalized variance function (GVF) parameters for BJS. The GVFs take into account aspects of the NCVS complex sample design and represent the curve fitted to a selection of individual standard errors based on the Jackknife Repeated Replication technique. The GVF parameters were used to generate standard errors for each point estimate (such as counts, percentages, and rates) in the report. For estimates, standard errors were based on the ratio of the sums of victimizations and respondents across years. **************************************************** ****************************************** Crime Victims with Disabilities Awareness Act (Public Law 105-301), 1998 ****************************************** The Crime Victims with Disabilities Awareness Act mandates that the National Crime Victimization Survey (NCVS) include statistics on crimes against people with disabilities and the characteristics of these victims. The act was designed “to increase public awareness of the plight of victims of crime with developmental disabilities, to collect data to measure the magnitude of the problem, and to develop strategies to address the safety and justice needs of victims of crime with developmental disabilities.” Section 5 of the act directed the Department of Justice to include statistics relating to “the nature of crimes against people with developmental disabilities; and the specific characteristics of the victims of those crimes” in the NCVS. This report is a part of the Bureau of Justice Statistics’ (BJS) series on crime against people with disabilities. More information can be found on the BJS website. Because of changes in the questionnaire, comparisons between 2007 data and later years should not be made. (See Methodology for more information on changes to the NCVS and ACS questionnaires.) **************************************************** In this report, BJS conducted tests to determine whether differences in estimated numbers and percentages were statistically significant once sampling error was taken into account. Using statistical programs developed specifically for the NCVS, BJS tested the significance of all comparisons in the text. The primary test procedure used was Student’s t- statistic, which tests the difference between two sample estimates. To ensure that the observed differences between estimates were larger than might be expected due to sampling variation, BJS set the significance level at the 95% confidence level. Differences described as slight or slightly passed a test at the 0.10 level of statistical significance (90% confidence level). Caution is required when comparing estimates not explicitly discussed in this report. Data users can use the estimates and the standard errors of the estimates provided in this report to generate a confidence interval around the estimate as a measure of the margin of error. The following example illustrates how standard errors can be used to generate confidence intervals: * According to the NCVS, during 2011 and 2012, 49.9 % of simple assault against persons with disabilities involved victims with multiple disability types (see table 6). Using the GVFs, BJS determined that the estimate has a standard error of 3.48% (see appendix table 6). A confidence interval around the estimate was generated by multiplying the standard errors by ±1.96 (the t-score of a normal, two-tailed distribution that excludes 2.5% at either end of the distribution). Therefore, the confidence interval around the 49.9% estimate from 2011 and 2012 is 49.9% + 3.48% x ± 1.96 or (43.08% to 56.72%). In others words, if different samples using the same procedures were taken from the U.S. population during 2011 and 2012, 95% of the time the percentage of violent crimes against persons with disabilities in which the victim had multiple disability types would fall between 43.08% and 56.72%. In this report, a coefficient of variation (CV), representing the ratio of the standard error to the estimate, was also calculated for all estimates. CVs provide a measure of reliability and a means to compare the precision of estimates across measures with differing levels or metrics. In cases where the CV was greater than 50%, or the unweighted sample had 10 or fewer cases, the estimate was noted with a “!” symbol (interpret data with caution; estimate based on 10 or fewer sample cases, or coefficient of variation is greater than 50%). *********************************************** Standard error computations and statistical significance for age-adjusted rates *** *********************************************** Footnote 3 ?For more information on computing standard errors for age-adjusted rates, see Anderson, R.N., & Rosenberg, H.M. (1998). Age Standardization of Death Rates: Implementation of the Year 2000 Standard. National Vital Statistics Reports, 47 (3). Available at http://www.cdc.gov/nchs/data/nvsr/nvsr47/nvs47_03.pdf.*** Due to the complexity in generating age-adjusted rates of violent crime, other methods were used to compute standard errors and determine statistical significance. For each age- adjusted rate, variances were computed for each age group- specific rate using information from the generalized variance function (GVF) parameters that the Census Bureau produced for the NCVS. For each age group, the variance was multiplied by the squared weight for that particular age group in the 2000 U.S. Standard Population. The result was then summed across all age groups to produce the variance for the age-adjusted rate. The square root of this variance was taken to produce the standard error of the age-adjusted rate. To calculate statistical significance among two age adjusted rates, the standard errors were computed for each rate. Next, the estimated standard error for the difference of the two rates was calculated. This was done by taking the square root of the sum of each rate’s squared standard error (that is, Se12 + Se22). The absolute difference in the rates was divided by the estimated standard error for the difference to generate a t-statistic. If the t-statistic was greater than 1.96, the difference was statistically significant. If it was equal to or less than 1.96, the difference between the two rates was not statistically significant. ************ 2011 rates ************ All 2011 rates of victimization presented in this report differ from those presented in the previous version of this report. The Census Bureau found an error with the 2011 single year incident level NCVS data file and its accompanying weight. The 2011 single year file was revised with a new weight; as a result, there was a slight change in the estimates. The 2011 rates were generated from the corrected data file and weight. **************************************************** The Bureau of Justice Statistics, located in the Office of Justice Programs, U.S. Department of Justice, collects, analyzes, and disseminates statistical information on crime, criminal offenders, victims of crime, and the operation of justice systems at all levels of government. William J. Sabol is acting director. These statistical tables were prepared by Erika Harrell, Ph.D. Rachel Morgan, Ph.D., provided verification. Morgan Young and Jill Thomas edited the report. Barbara Quinn produced the report. February 2014, NCJ 244525 ***************************************************** ************************************************** Office of Justice Programs Innovation * Partnerships * Safer Neighborhoods www.ojp.usdoj.gov ************************************************** ********************** 2/10/2014/JER/3:15pm **********************